Add free-threaded 3.14 to the CI

Author: hugovk

.github/workflows/ci.yml

@@ -9,7 +9,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python: ['3.10', '3.11', '3.12', '3.13', '3.14']
+        python: ['3.10', '3.11', '3.12', '3.13', '3.14', '3.14t']
 
     steps:
       - name: Checkout